• 대한조선학회 특별논문집
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• 대한조선학회 2015년도 특별논문집
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• pp.1-8
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• 2015

In general, the strength assessment for heavy lift vessel is carried out under two stages. The first stage is to comply with the requirement of KR (Korean Register of Shipping) Steel Barges and Rules for Classification of Steel Ships. At the second stage, the structural strength analysis by Finite Element Method is peformed. This paper describes the strength assessment considering various loads for the heavy lift vessel of sheerleg type.

• 전기학회논문지
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• 제57권3호
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• pp.466-472
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• 2008

The paper concerns Fuzzy C-Means clustering based fuzzy neural networks (FCM-FNN) and the optimization of the network is carried out by means of hierarchal fair competition-based parallel genetic algorithm (HFCPGA). FCM-FNN is the extended architecture of Radial Basis Function Neural Network (RBFNN). FCM algorithm is used to determine centers and widths of RBFs. In the proposed network, the membership functions of the premise part of fuzzy rules do not assume any explicit functional forms such as Gaussian, ellipsoidal, triangular, etc., so its resulting fitness values directly rely on the computation of the relevant distance between data points by means of FCM. Also, as the consequent part of fuzzy rules extracted by the FCM-FNN model, the order of four types of polynomials can be considered such as constant, linear, quadratic and modified quadratic. Since the performance of FCM-FNN is affected by some parameters of FCM-FNN such as a specific subset of input variables, fuzzification coefficient of FCM, the number of rules and the order of polynomials of consequent part of fuzzy rule, we need the structural as well as parametric optimization of the network. In this study, the HFCPGA which is a kind of multipopulation-based parallel genetic algorithms(PGA) is exploited to carry out the structural optimization of FCM-FNN. Moreover the HFCPGA is taken into consideration to avoid a premature convergence related to the optimization problems. The proposed model is demonstrated with the use of two representative numerical examples.

• Advanced Composite Materials
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• 제17권1호
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• pp.1-23
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• 2008

Robotized filament winding technology involves a robot that winds a roving impregnated by resin on a die along the directions of stresses to which the work-piece is submitted in applications. The robot moves a deposition head along a winding trajectory in order to deposit roving. The trajectory planning is a very critical aspect of robotized filament winding technology, since it is responsible for both the tension constancy and the winding time. The present work shows two original rules to plan the winding trajectory of structural parts, whose shape is obtained by sweeping a full section around a 3D curve that must be closed and not crossing in order to assure a continuous winding. The first rule plans the winding trajectory by approximating the part 3D shape with straight lines; it is called the discretized rule. The second rule defines the winding trajectory simply by offsetting a 3D curve that reproduces the part 3D shape, of a defined distance; it is called the offset rule. The two rules have been compared in terms of roving tension and winding time. The present work shows how the offset rule enables achievement of both the required aims: to manufacture parts of high structural performances by keeping the tension on the roving near to the nominal value and to markedly decrease the winding time. This is the first step towards the optimization of the robotized filament winding technology.

• 대한조선학회 특별논문집
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• 대한조선학회 2015년도 특별논문집
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• pp.46-49
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• 2015

Common Structural Rules (CSR) about bulk carriers and double-hull oil tankers of International Association of Classification Societies (IACS) has been applied to ships contracted for construction since April 2006. By unifying each society's rules, the difference of opinion in the between shipyard and ship owners, classification was reduced, and CSR has been evaluated by rules the safety structure more enhanced. However, The CSR about the bulk carriers and double hull oil tankers, important design content standards, such as the local scantling calculation, static/dynamic load case and corrosion margin and etc., are different. Therefore in order to combine the CSR, the Harmonized CSR for bulk carriers and double hull oil tankers (H-CSR) was issued on 1, January, 2014, and will be apply to ships contracted for construction after 1st July 2015. It is necessary to verify the H-CSR to optimize the structural arrangement because effective date is not far off. In this study, we compared the impact by rule change for the hull girder shear strength of bulk carriers between CSR and H-CSR in respect of the yielding and buckling strength.

• 한국해양공학회지
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• 제28권1호
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• pp.77-84
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• 2014

Recently, CFRP composites have often been used as the materials for lightweight pleasure yacht hulls. Because CFRP composites not only make the hull light but also have good physical characteristics, in the leading countries of the marine industries, CFRP yachts are being sold at a higher price. The design and construction of FRP composite yachts, including those made of CFRP, have to follow rules based on ISO 12215, such as the hull structure rules of the international classification societies. On the other hand, there are no rules related to CFRP composites in the Guidance for Recreational Crafts, which was newly revised by the Korean Register of Shipping. In this paper, ISO 12215-5 and Part B, RINA Pleasure Yacht (REGISTRO ITALIANO NAVALE) on the design pressure and scantling of CFRP hull structures are compared and analyzed. Through a comparative study and the application to a cruise yacht design, we try to understand how to design CFRP hull structures using the international standards, ISO 12215, and the rules of the international classification society, RINA.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.225-234
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• 2020

Reliability-based structural optimization usually requires designers or engineers model different designs manually, which is considered very time consuming and all possibilities cannot be fully explored. Otherwise, a lot of time are needed for designers or engineers to learn mathematical modeling and programming skills. Therefore, a framework that integrates generative design, structural simulation and reliability theory is proposed. With the proposed framework, various designs are generated based on a set of rules and parameters defined based on visual programming, and their structural performance are simulated by OpenSees. Then, reliability of each design is evaluated based on the simulation results, and an optimal design can be found. The proposed framework and prototype are tested in the optimization of a steel frame structure, and results illustrate that generative design based on visual programming is user friendly and different design possibilities can be explored in an efficient way. It is also reported that structural reliability can be assessed in an automatic way by integrating Dynamo and OpenSees. This research contributes to the body of knowledge by providing a novel framework for automatic reliability evaluation and structural optimization.

• 디지털융복합연구
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• 제12권1호
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• pp.23-36
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• 2014

최근 경제위기가 세계경제의 불안정을 가져왔다. 각 국가는 경기안정을 위해 재정준칙을 도입하거나 강화하고 있다. 국가재정정책은 현재와 미래의 경제상황을 결정하는 중요한 역할을 한다. 기존 회계규칙을 엄격히 제한한 재정준칙은 재정적자를 극복하고 재정안정화 범위를 확대하여 재정구조를 위한 재정정책으로 사용할 수 있다. 그러나 재정준칙은 자신의 재정상황, 정치적 상황에 따라 다양한 형태와 방법으로 운영되고 있다. 본 연구는 성공적인 국가재정시스템 및 지속적인 재정건전성과 발전에 대한 주요 요소를 제시하였다.

• Structural Engineering and Mechanics
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• 제9권5호
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• pp.505-518
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• 2000

A major cause of premature debonding of tension face plates is shear peeling (Jones et al. 1988, Swamy et al. 1989, Ziraba et al. 1994, Zhang et al. 1995), that is debonding at the plate ends that is associated with the formation of shear diagonal cracks that are caused by the action of vertical shear forces. It is shown in this paper how side plated beams are less prone to shear peeling than tension face plated beams, as the side plate automatically increases the resistance of the reinforced concrete beam to shear peeling. Tests are used to determine the increase in the shear peeling resistance that the side plates provide, and also the effect of vertical shear forces on the pure flexural peeling strength that was determined in the companion paper. Design rules are then developed to prevent premature debonding of the plate ends due to peeling and they are applied to the strengthening and stiffening of continuous reinforced concrete beams. It is shown how these design rules for side plated beams can be adapted to allow for propped and unpropped construction and the time effects of creep and shrinkage, and how side plates can be used in conjunction with tension face plates.

• Steel and Composite Structures
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• 제36권3호
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• pp.273-291
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• 2020

Two-storey X-bracings are currently very popular in European practice, as respect to chevron and simple X bracings, owing to the advantages of reducing the bending demand in the brace-intercepted beams in V and inverted-V configurations and optimizing the design of gusset plate connections. However, rules for two-storey X braced frames are not clearly specified within current version of EN1998-1, thus leading to different interpretations of the code by designers. The research presented in this paper is addressed at investigating the seismic behaviour of two-storey X concentrically braced frames in order to revise the design rules within EN1998-1. Therefore, five different design criteria are discussed, and their effectiveness is investigated. With this aim, a comprehensive numerical parametric study is carried out considering a set of planar frames extracted from a set of structural archetypes that are representative of regular low, medium and high-rise buildings. The obtained results show that the proposed design criteria ensure satisfactory seismic performance.

• 한국의류학회지
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• 제26권9호
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• pp.1378-1389
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• 2002

This study was to identify dimensions of subjective knowledge and to test the structural model of the effect of subjective knowledge on information search and evaluation rules for apparel products. A questionnaire was administered to 668 females living in Seoul, Taejon, and Cheongju, and the data were analysed by using LISREL 8. The results of this study were as follows: First, consumers' subjective knowledge regarding apparel products consisted of five factors; Style knowledge, Fashion Knowledge, Store Knowledge, Fabric/Management Knowledge, and Brand knowledge. Those factors were influenced by the experience related with apparel products. Second, the subjective knowledge influenced information searches. That is, internal search was significantly influenced by fashion knowledge and store knowledge, while external search was significantly influenced by fashion knowledge and fabric/management knowledge. Third, the subjective knowledge had indirect effects on evaluation rules via search activities (e.g., internal and external), suggesting that the internal search was mediated in relationship between subjective knowledge and compensatory rule, while the urtemal search was mediated in the relationship between subjective knowledge and noncompensatory rule. Therefore, this study implies that subjective knowledge plays an important role to explain consumers' decision making processes such as information search and evaluation.